Facilitated diffusion
<span>The word 'diffusion' means free movement across distance, with or without the presence of a barrier. However, there is a phenomenon known as facilitated diffusion which occurs at the cellular level. The cell does not allow free radicals and other harmful substances to enter and harm the cell organs. This is possible due to the structure of the cell membrane. The structure is such that, it allows only certain things to pass in and out of the cell. One such activity that allows selective movement in and out of the cell is the process of facilitated diffusion.</span>
Operons are the functional units of transcription and genetic regulation. These are found in bacteria and their viruses where genes coding for functionally related proteins are grouped along the DNA.
The two types of operons are- inducible and repressible.
They regulate the genes as in negative inducible operons, a regulatory repressor protein is bound to the operator. It prevents the transcription of the genes on the operon. If positive inducer is present, it binds to the repressor and changes its conformation so it is unable to bind to the operator.
Viruses are not made out of cells, they can't keep themselves in a stable state, they don't grow, and they can't make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.
Answer:
there are not 7 steps of primary succesion and they only have 4 steps.
Explanation:
The complete process of a primary autotrophic ecological succession involves the following sequential steps, which follow one another:
Nudation:
Invasion:
Competition and reaction:
Stabilization or climax:
